The present invention generally relates to liquid pumps and more specifically to blood pumps used for example in open-heart surgery or cardiovascular procedures. The blood pump of the present invention is of the same general type of blood pump invented by me and disclosed in U.S. Pat. No. 5,368,438 and No. 5,501,574. However the blood pump of the present invention incorporates highly useful and novel improvements over the aforementioned blood pump as well as others of the prior art.